Differences in the regulation of aldehyde dehydrogenase genes in Aspergillus niger and Aspergillus nidulans

In order to study mechanisms of gene regulation in A. niger, and to compare these to similar systems in A. nidulans, a gene encoding an aldehyde dehydrogenase enzyme has been cloned. In wild-type strains of A. niger the gene shows expression which is regulated by induction and repression. Levels of induction by various compounds and the extent of repression under various growth conditions differs from that seen for the A. nidulans aldA gene. Unlike the A. nidulans aldA gene, the A. niger gene has both carbon catabolite repressible and nonrepressible induction mechanisms. Studies of heterologous expression of the A. niger gene in A. nidulans have shown that its expression is regulated by the alcR gene product of A. nidulans.